(PHP 4, PHP 5, PHP 7)
setcookie — Send a cookie
$name
[, string $value
= ""
[, int $expire
= 0
[, string $path
= ""
[, string $domain
= ""
[, bool $secure
= false
[, bool $httponly
= false
]]]]]] )setcookie() defines a cookie to be sent along with the rest of the HTTP headers. Like other headers, cookies must be sent before any output from your script (this is a protocol restriction). This requires that you place calls to this function prior to any output, including <html> and <head> tags as well as any whitespace.
Once the cookies have been set, they can be accessed on the next page load with the $_COOKIE array. Cookie values may also exist in $_REQUEST.
» RFC 6265 provides the normative reference on how each setcookie() parameter is interpreted.
name
The name of the cookie.
value
The value of the cookie. This value is stored on the clients computer;
do not store sensitive information. Assuming the
name
is 'cookiename', this
value is retrieved through $_COOKIE['cookiename']
expire
The time the cookie expires. This is a Unix timestamp so is in number of seconds since the epoch. In other words, you'll most likely set this with the time() function plus the number of seconds before you want it to expire. Or you might use mktime(). time()+60*60*24*30 will set the cookie to expire in 30 days. If set to 0, or omitted, the cookie will expire at the end of the session (when the browser closes).
Note:
You may notice the
expire
parameter takes on a Unix timestamp, as opposed to the date format Wdy, DD-Mon-YYYY HH:MM:SS GMT, this is because PHP does this conversion internally.
path
The path on the server in which the cookie will be available on.
If set to '/', the cookie will be available
within the entire domain
. If set to
'/foo/', the cookie will only be available
within the /foo/ directory and all
sub-directories such as /foo/bar/ of
domain
. The default value is the
current directory that the cookie is being set in.
domain
The (sub)domain that the cookie is available to. Setting this to a subdomain (such as 'www.example.com') will make the cookie available to that subdomain and all other sub-domains of it (i.e. w2.www.example.com). To make the cookie available to the whole domain (including all subdomains of it), simply set the value to the domain name ('example.com', in this case).
Older browsers still implementing the deprecated » RFC 2109 may require a leading . to match all subdomains.
secure
Indicates that the cookie should only be transmitted over a
secure HTTPS connection from the client. When set to TRUE
, the
cookie will only be set if a secure connection exists.
On the server-side, it's on the programmer to send this
kind of cookie only on secure connection (e.g. with respect to
$_SERVER["HTTPS"]).
httponly
When TRUE
the cookie will be made accessible only through the HTTP
protocol. This means that the cookie won't be accessible by
scripting languages, such as JavaScript. It has been suggested that
this setting can effectively help to reduce identity theft through
XSS attacks (although it is not supported by all browsers), but that
claim is often disputed. Added in PHP 5.2.0.
TRUE
or FALSE
If output exists prior to calling this function,
setcookie() will fail and return FALSE
. If
setcookie() successfully runs, it will return TRUE
.
This does not indicate whether the user accepted the cookie.
Some examples follow how to send cookies:
Example #1 setcookie() send example
<?php
$value = 'something from somewhere';
setcookie("TestCookie", $value);
setcookie("TestCookie", $value, time()+3600); /* expire in 1 hour */
setcookie("TestCookie", $value, time()+3600, "/~rasmus/", "example.com", 1);
?>
Note that the value portion of the cookie will automatically be urlencoded when you send the cookie, and when it is received, it is automatically decoded and assigned to a variable by the same name as the cookie name. If you don't want this, you can use setrawcookie() instead if you are using PHP 5. To see the contents of our test cookie in a script, simply use one of the following examples:
<?php
// Print an individual cookie
echo $_COOKIE["TestCookie"];
// Another way to debug/test is to view all cookies
print_r($_COOKIE);
?>
Example #2 setcookie() delete example
When deleting a cookie you should assure that the expiration date is in the past, to trigger the removal mechanism in your browser. Examples follow how to delete cookies sent in previous example:
<?php
// set the expiration date to one hour ago
setcookie ("TestCookie", "", time() - 3600);
setcookie ("TestCookie", "", time() - 3600, "/~rasmus/", "example.com", 1);
?>
Example #3 setcookie() and arrays
You may also set array cookies by using array notation in the cookie name. This has the effect of setting as many cookies as you have array elements, but when the cookie is received by your script, the values are all placed in an array with the cookie's name:
<?php
// set the cookies
setcookie("cookie[three]", "cookiethree");
setcookie("cookie[two]", "cookietwo");
setcookie("cookie[one]", "cookieone");
// after the page reloads, print them out
if (isset($_COOKIE['cookie'])) {
foreach ($_COOKIE['cookie'] as $name => $value) {
$name = htmlspecialchars($name);
$value = htmlspecialchars($value);
echo "$name : $value <br />\n";
}
}
?>
以上例程会输出:
three : cookiethree two : cookietwo one : cookieone
版本 | 说明 |
---|---|
5.5.0 | A Max-Age attribute is now included in the Set-Cookie header sent to the client. |
5.2.0 |
The httponly parameter was added.
|
Note:
You can use output buffering to send output prior to the call of this function, with the overhead of all of your output to the browser being buffered in the server until you send it. You can do this by calling ob_start() and ob_end_flush() in your script, or setting the output_buffering configuration directive on in your php.ini or server configuration files.
Note:
If the PHP directive register_globals is set to on then cookie values will also be made into variables. In our examples below, $TestCookie will exist. It's recommended to use $_COOKIE.
Common Pitfalls:
expire
parameter. A nice way to debug the existence of cookies is by
simply calling print_r($_COOKIE);.
FALSE
, and all other arguments
match a previous call to setcookie, then the cookie with the specified
name will be deleted from the remote client.
This is internally achieved by setting value to 'deleted' and expiration
time to one year in past.
FALSE
will try to delete the cookie,
you should not use boolean values. Instead, use 0 for FALSE
and 1 for TRUE
.
Multiple calls to setcookie() are performed in the order called.